### Rydberg's formula

Posted:

**Tue Oct 17, 2017 3:57 pm**I don't really understand what Rydberg's formula is about and the meaning of the different levels. Also, will the series we are starting from and jumping to be given?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=27&t=22354

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Posted: **Tue Oct 17, 2017 3:57 pm**

I don't really understand what Rydberg's formula is about and the meaning of the different levels. Also, will the series we are starting from and jumping to be given?

Posted: **Tue Oct 17, 2017 7:46 pm**

Different levels signify the different energies the electrons will possess when in that level. Rydberg's equation correlates energy levels with the frequency of the electron in that level.

It depends on the question. Sometimes, they may want you to find out the initial or final energy level using the wavelength or frequency, which will be given.

It depends on the question. Sometimes, they may want you to find out the initial or final energy level using the wavelength or frequency, which will be given.

Posted: **Tue Oct 17, 2017 7:49 pm**

It's easier to think about in terms of E=-hR/n^2. Then, calculated the change of final-initial. Or use energy to get wavelength or frequency. Hope this helps!

Posted: **Thu Oct 19, 2017 9:28 am**

Another equation is v=R(1/n1^2-1/n2^2)

Posted: **Thu Oct 19, 2017 12:13 pm**

Rydberg's equation is used when you want to find the wavelength, frequency, or energy of an electron moving from one level to another. Most of the time you will be given the starting and final energy levels (n1 and n2), but sometimes the question might ask you to solve for n1 or n2. In this case, make sure you always remember to take the square root.

In terms of using Rydberg's equation, it sometimes can get confusing. If you find that you are always getting an incorrect answer using it, you can use E=-hR/n^2. To use this equation, you plug in n1, and then use the equation again for n2. Once you have your 2 values, you find the ΔE, which is calculated by doing your final value minus your initial value (so n2-n1 if it is going from n1 to n2). Since ΔE is equal to hv, you are still able to find the frequency.

In terms of using Rydberg's equation, it sometimes can get confusing. If you find that you are always getting an incorrect answer using it, you can use E=-hR/n^2. To use this equation, you plug in n1, and then use the equation again for n2. Once you have your 2 values, you find the ΔE, which is calculated by doing your final value minus your initial value (so n2-n1 if it is going from n1 to n2). Since ΔE is equal to hv, you are still able to find the frequency.

Posted: **Thu Oct 19, 2017 12:16 pm**

I'm also confused as to when to make the value of r negative. I know lavelle mentioned that it was negative if energy was released, but I have yet to see a problem where it needed to be negative.

Posted: **Fri Oct 20, 2017 12:01 am**

Rydberg's formula is used for finding the wavelength, energy, or frequency of an electron that is moving from one level to the next. Usually you the initial and final levels will be given, but in some other cases, the question will ask for the initial and the final. So that's when you used the formula v=R(1/n(initial)^2 - 1/n(final)^2).